1. Field of the Invention
One disclosed aspect of the embodiments relates to image capturing devices.
2. Description of the Related Art
An image capturing device, such as a complementary metal-oxide semiconductor (CMOS) image sensor, includes a pixel circuit region in which pixel circuits are arranged and a peripheral circuit region in which peripheral circuits are arranged. Different circuit layouts are employed for the pixel circuit region and the peripheral circuit region. Therefore, with regard to an insulation layer located at the same height as or higher than electrodes and conductive lines, a difference in height may occur between the pixel circuit region and the peripheral circuit region in accordance with the density of the electrodes and the conductive lines. Furthermore, when a planarization process is performed on the insulation layer, there is a problem in that a difference in height may occur between a central part and a peripheral part of the pixel circuit region. A difference in height between the central part and the peripheral part of the pixel circuit region may lead to a difference in signal outputs from the central part and the peripheral part of the pixel circuit region, causing reduction in image quality.
As a countermeasure against this problem, Japanese Patent Laid-Open No. 2009-94299 discusses providing a pixel region with a first layer composed of a transparent material at the same level as at least one of an electrode layer and a wiring layer.
When the first layer is formed in the pixel region as in Japanese Patent Laid-Open No. 2009-94299, damages may occur during the forming process of the first layer or an optical loss may occur due to the existence of the first layer, possibly causing reduction in image quality. Therefore, one disclosed aspect of the embodiments provides an image capturing device that can obtain a higher-quality image.